Computer operating systems commonly allow the customization of application windows on the display screen. Users may minimize, maximize, tile, or control the size and screen location of the windows of the different applications currently running on their computer. These techniques are often designed for ease of use and compatibility with commonly used computer input devices, such as a mouse and keyboard. For example, window resizing may commonly be done by a user by hovering the mouse cursor over a small designated target location at a corner of the application window to be resized. The user then presses and holds the mouse button and then drags the mouse to resize the application window, setting a different size and shape for the window. Similarly, many computer operating systems allow users to move application windows around the display screen by mouse-clicking on a different specific target location on the application window, and then dragging the window to a different location.
As computer operating system input devices have evolved, pen input devices have become common tools for interacting with operating systems on tablet personal computers (tablet PCs), personal digital assistants (PDAs), and similar pen-supported computing devices. Pen input devices are pointed writing instruments which allow users to “draw” on their computer screen as though they were writing with an ink pen on a piece of paper. For example, a pen input device may be an electromagnetic digital pen compatible with certain tablet PCs, or it may be a simple touch pen or stylus compatible with certain tablet PCs and many PDAs having touch digitizers. A pen input device may also support taps and drags to perform the same functions as a mouse does performs with clicks and drags. Thus, in a tablet PC or any device with which a pen input device may be used rather than or in addition to a mouse, users commonly move and resize application windows using taps and drags, similar to the way that a mouse user might perform these operations.
However, operating system tasks such as these, which were originally designed for mouse input devices, may potentially be more difficult to perform with pen input devices, since subtle movements such as taps or drags into small target areas may require greater motor control. Additionally, pen input targeting errors may result when a user holds a pen at an angle, electromagnetic interference may affect a digitizer's electromagnetic field, and the pen input might not be accurately calibrated to the digitizer. These and other potential problems may cause many operating system tasks to be less reliable or more tedious with a pen input device. Thus, in current operating systems, using a pen input device to resize or reposition application windows may be considerably more difficult than using a mouse to perform the same tasks.
As PDAs and tablet PCs with pen input devices have gained in popularity, some efforts have been made to improve the usability of pen input devices with respect to such tasks as window resizing and repositioning. In one attempt, the target area that the user taps on the display screen to resize a window was made larger to allow users to more easily tap that area and resize the window. However, solutions such as this unnecessarily waste valuable limited space on the display screen, which for devices such as tablet PCs or PDAs may already be smaller then standard display screens. This problem is further compounded when a user has many application windows open concurrently on the screen.